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x+y=-5 (x+y)(x-y)-10y=-5(x-y)-10y =-5(x-

2026-09-07 19:28:20 灵风评论 社会

x+y=-5
(x+y)(x-y)-10y=-5(x-y)-10y
=-5(x-y+2y)=-5(x+y)=-5*-5=25

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